非饱和多孔介质中混合元法的化学-热-渗流-力学耦合的本构模拟

The coupled chemo-thermo-hydro-mechanical constitutive modeling for the mixed finite element of unsaturated porous media

在文献[1]中建立的多孔介质中化学-热-渗流-力学(CTHM)本构模型基础上,针对文献[2]建立的非饱和多孔介质中热-渗流-力学耦合分析的混合有限元方法,发展了非饱和多孔介质中混合元的化学-热-渗流-力学(CTHM)耦合本构模拟算法。采用非关联流动多重屈服准则模拟非饱和多孔介质的材料非线性行为。推导了u-pw-pa-T形式的包含了耦合率本构方程积分的向后欧拉映射算法和一致性弹塑性切线模量矩阵(单元刚度矩阵)的混合元一致性算法。本文给出了临界状态线(CSL)和状态边界面(SBS)两个屈服准则的一致性算法。数值结果显示了本文所发展的混合元耦合本构模拟算法在模拟由热、化学、力学荷载共同引起的多孔介质中化学-热-渗流-力学(CTHM)耦合行为的能力和有效性。

An algorithm for the chemo-thermo-hydro-mechanical（CTHM） constitutive modelling, aiming to the chemo-thermo-hydro-mechanical constitutive model of porous media proposed in reference[1], is developed for the mixed finite element method in the coupled thermo-hydro-mechanical analysis of unsaturated media present in reference[2]. A multi-surface yield criterion using non-associated flow rule is adopted to simulate the material non-linearity of unsaturated porous media. A return mapping algorithm for the integration of the rate constitutive equation and the consistent elasto-plastic tangent modulus matrix as well as the consistent elasto-plastic tangent stiffness matrix of the mixed element with the u-pw- pa-T form are derived. The consistent algorithms for the two component yield surfaces, i.e. the Critical State Line （CSL） and the State Boundary Surface （SBS） criteria, are particularly given in this paper. The numerical results demonstrate the capability and the validity of the present algorithm of mixed finite element constitutive modelling in simulating the coupled chemo-thermo-hydro-mechanical behaviour in porous media caused by the thermo-chemo-mechanical loading.